VERTICAL RECOMMENDATIONS

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by 2I0KIC, Nov 8, 2019 at 4:46 PM.

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  1. 2I0KIC

    2I0KIC Ham Member QRZ Page

    Hello Everyone, I am looking for advice from anyone using or has used or even know about the following three HF VERTICALS. As for me radial wire's is out of the question.
    The antennas are :
    DIAMOND CP6S
    DIAMOND BB7V
    COMET CHA 25O BX11

    Any feedback would be very much appreciated
    Take Care You And Yours 73s
    KEVIN, 2I0KIC, ARMAGH
     
  2. N8CMQ

    N8CMQ Ham Member QRZ Page

    I have only used a trap vertical, kind of like the Diamond CP6S, but ground mounted with a ton of ground radials.
    I looked at the Diamond BB7V and found it is a transformer connected to power resistors and an element connected to the resistors.
    I don't know the Comet antenna.

    What are your plans for the antenna? Are you going to mount it high on a mast or ground mount it?
     
    NH7RO likes this.
  3. W9GB

    W9GB Ham Member QRZ Page

    OK. You defined your requirements, and in this instance reduced your solutions.
    The three (3) candidates you listed are Compromises (not highly efficient) antennas,
    limited in Power (Watts) due to Matching Networks AND they are NOT Cheap (~ $400 USD).


    1. Quarter-Wavelength Vertical (Marconi) requires Radials, So Scratch those designs.
    2. Counterpoise wires with End-Fed Halfwave (EFHW) antenna common.
    3. Vertical Half-Wave antennas fed at mid-point are more complicated, expensive.

    Suggest you SEARCH YouTube for those 3 antennas ... to WATCH various Reviews/Installs.
    ==
    Diamond CP6AR : $419.99 USD
    https://www.dxengineering.com/parts/dmn-cp6ar
    Manual : This antenna uses traps for multi-band performance.
    https://www.diamondantenna.net/pdfdocs/CP6AR.pdf
    eHam.net reviews
    https://www.eham.net/reviews/view-product?id=12751

    Diamond BB7V : $399.95 USD
    Often mentioned as Diamond’s version of the Comet CHA 250 antenna
    https://www.dxengineering.com/parts/dmn-bb7v
    eHam.net reviews
    https://www.eham.net/reviews/view-product?id=5936

    Comet CHA 250 : $ 429.99 USD

    https://www.dxengineering.com/parts/cma-cha-250b
    Comet web page
    http://www.cometantenna.com/amateur-radio/base-antennas/multi-band-hfvhfuhf-2/
    eHam.net reviews
    https://www.eham.net/reviews/view-product?id=5175
    ===
    ANATOMY of the COMET CHA-250BXII (What’s INSIDE Matters)
    by Iain Crawford, VK5ZD
    http://www.vk5zd.com/CHA250/CHA250.aspx

    An Explanation of the Comet CHA250 Vertical Antenna
    by Owen Duffy, VK1OD
    https://owenduffy.net/antenna/misc/CHA250.htm
    In summary then, the CHA250 would appear to be an 18 meter vertical,
    fed at 7 meters from the top by a non-ideal, lossy 1:4 transformer.



    Diamond BB7V with Peter Waters, G3OJV on YouTube
     
    Last edited: Nov 8, 2019 at 5:32 PM
  4. W9GB

    W9GB Ham Member QRZ Page

    I forgot one.

    Review (what’s inside, how they work) Broadband HF verticals:
    Comet CHA-250B / VA250 / HA-750BL / Falcon OUT-250-B / GP2500F / JTV680

    and the Diamond BB6W & BB7V
    by Martin Ehrenfried, G8JNJ
    https://www.g8jnj.net/cometcha250b.htm

    The Main Problem would seem to be the suggestion that the antenna will work with no radials, ground plane or counterpoise wires.
    This means that if none of these are installed, the antenna will use the coax cable as part of the radiating structure. This can (and does) produce in very unpredictable results.

    I would strongly suggest that some form of ground plane is used. Either ground mount the antenna and connect at least 4 radial wires to the outer screen of the coax at the base of the antenna, or if the antenna is mounted on a pole, add a minimum of three sloping radials (at least 5m long) as this can dramatically improve the performance.

    Many people had unrealistic expectations of antenna performance, especially on 3.6MHz where comparisons were made with dipoles, frequently for medium distance contacts.
    The antenna is electrically short on 3.6MHz , so even if an auto-tuner is used the performance will still be 3-4dB down on a 1/4 wave vertical (20m high).
    The loss in the matching transformer (signal in dB) at this frequency reduces the gain by a further 13dB, so the total gain at 3.6 MHz is about 17dB less than a 1/4 wave vertical.
    The other factor is the lack of NVIS coverage which makes a big difference for semi to local contacts on 3.6MHz.
     
    Last edited: Nov 8, 2019 at 5:49 PM
  5. NH7RO

    NH7RO Ham Member QRZ Page

    Suggestion: Scratch all three off your list and consider something like KX4O's clever asymmetrically hatted vertical dipole instead. No radials yet good performance and easy set-up and take-down (if necessary).

    While it you will be limited to 20-10 meters it would be a lot simpler to implement in a restricted antenna environment---and would be a lot more efficient than the ones you are considering. Pre-drilled mounting plates are sold by DXE and the aluminum tubing and jubilee clips should be available locally.

    https://www.hamradio.me/antennas/asymmetrical-hatted-dipole-antenna-prototype.html

    73,

    Jeff

    PS: Transworld Antennas and Pro AntennasUK also make compact vertical dipoles that can play on 40 meters as well as the higher bands---but are more costly.
     
    Last edited: Nov 8, 2019 at 6:02 PM
  6. W2AAT

    W2AAT XML Subscriber QRZ Page

    You might want to check out GAP verticals.
     
    N5SMO, WB5YUZ and NH7RO like this.
  7. AA7QQ

    AA7QQ Ham Member QRZ Page

    Even if you can ground mount with just 4-30'ish radials, a 6BTV will outperform them.
    I did not read the part about no radials.
    So, a 6BTV ground mounted with just a ground rod will do.
    Ed
     
  8. KH6AQ

    KH6AQ Ham Member QRZ Page

    The Diamond CP6S should outperform the other two antennas. It's a trap vertical with one loaded radial per band while the others use a lossy circuit to obtain wide bandwidth.

    The Champion vertical antenna book compares the CP6S against ground mounted full size verticals having 64 radials.

    CP6S relative gain:

    80M, -13 dB
    40M, -5 dB
    20M, -6 dB
    15M, -1 dB
    10M, +2 dB
     
  9. 2I0KIC

    2I0KIC Ham Member QRZ Page

    Hello Everyone, a huge thanks to everyone that took the time io reply to my post about vertical antennas.
    I will read them in detail tonight.
    One thing I omitted to say I have a MFJ 993B Auto ATU, that I use on my HALF-SIZE G5RV it's a sloper from the pole on my chimney (single storey house) that my Watson W50 2/70 Collinear is on down to my back fence luckily it just fits.
    Again sorry to everyone that replied, and I wonder if the Auto ATU make any difference to your answers?
    TAKE CARE YOU AND YOURS 73s
    Have A Good And Safe Weekend Everyone
    KEVIN, 2I0KIC, ARMAGH
     
    Last edited: Nov 9, 2019 at 3:59 PM
  10. 2I0KIC

    2I0KIC Ham Member QRZ Page


    Hello Everyone, a huge thanks to everyone that took the time io reply to my post about vertical antennas.
    I will read them in detail tonight.
    One thing I omitted to say I have a MFJ 993B Auto ATU, that I use on my HALF-SIZE G5RV it's a sloper from the pole on my chimney (single storey house) that my Watson W50 2/70 Collinear is on down to my back fence luckily it just fits.
    Again sorry to everyone that replied, and I wonder if the Auto ATU make any difference to your answers?
    TAKE CARE YOU AND YOURS 73s
    Have A Good And Safe Weekend Everyone
    KEVIN, 2I0KIC, ARMAGH
     

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